Interleukin-1 beta (C-511T) genetic polymorphism is associated with cognitive performance in elderly males without dementia.

Interleukin-1 beta (IL-1 beta), a proinflammatory cytokine, plays a significant role in age-related changes in long-term potentiation (a biological substrate for learning and/or memory) in the hippocampus of experimental animals. This study tests the hypothesis that a biallelic functional polymorphism in the promoter region (position-511) (rs16944) of the IL-1 beta gene is associated with cognitive performance in elderly males without dementia. A total of 161 elderly male subjects without major psychiatric disorders or dementia participated in this research. Cognitive functions were assessed by the Cognitive Abilities Screening Instruments (CASI) test as well as The Wechsler Digit Span Task test. A significant association was found between the IL-1 beta C-511T polymorphism and CASI score (p=0.008), particularly in the abstraction and judgment subtest (p=0.010), and the backward digit span test (p=0.004). Post hoc tests indicated that the C/C genotype gained better cognitive function test results than T/T carriers, mainly in the non-apolipoprotein E allele epsilon 4 carriers. These results suggest that genetic variants of the IL-1 beta C-511T polymorphism may play a role in specific cognitive functions in normal aged males. Considering that cognitive decline in the elderly is associated with local inflammation processes, genetic variants of cytokines and their receptors should be tested to improve gene-based prediction of general cognitive function in the elderly.